Low-temperature co-fired microwave dielectric ceramic material, and preparation method and application thereof

ABSTRACT

A low-temperature co-fired microwave dielectric ceramic material includes: (a) 85 wt % to 99 wt % ceramic material comprising Mg 2 SiO 4 , Ca 2 SiO 4 , CaTiO 3 , and CaZrO 3 , wherein a weight ratio of Mg 2 SiO 4  relative to Ca 2 SiO 4  is of (1-x): x, a weight ratio of CaTiO 3  relative to CaZrO 3  is of y:z, and a weight ratio of entities of Mg 2 SiO 4  and Ca 2 SiO 4  relative to CaTiO 3  is of (1-y-z):y, 0.2≤x≤0.7, 0.05≤y≤0.2, 0.05≤z≤0.4; and (b) 1 wt % to 15 wt % glass material composed of Li 2 O, BaO, SrO, CaO, B 2 O 3 , and SiO 2 .

CROSS REFERENCE OF THE INVENTION

The present application is a continuation in part application of U.S.patent application Ser. No. 15/597,011, filed on May 16, 2017; thecontent thereof is incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a microwave dielectric material, andits preparation method and application, and more particularly, toproducing a microwave dielectric material prepared through the techniqueof low-temperature co-fired ceramic.

Description of the Prior Art

Current communication industry development requiresmulti-functionalities and miniaturization of the wireless communicationdevices. Modularization of the radio frequency (RF) circuit has becomekey to development in the industry. In such development,resistance-capacitance delay (RC delay) has become more intensive due tothe shrinking distance between the transmission lines of microwavedevice, resulting in an increase of interference and power consumptionwhen an electronic signal is transferring among metals. Moreover, thelow-temperature, co-fired ceramic material and process technologythereof is widely used in applications of microwave devices and is a keytechnique that has become the focus of the industrial field indeveloping communications components such as, for example: filters,couplers, antennae etc. To solve the problem of RC delay and provide theproperties of co-firing ceramics at low temperatures, the presentinvention discloses a material with low dielectric constant which canco-fire with low-melting-point metal electrodes, such as Ag or Cu, etc.at a low temperature. With the increasing demand for communicationindustry, the annual global market growth rate of the microwave ceramicmaterial applied in the microwave ceramic capacitor has been about 15%.

Conventional materials of low dielectric constant include silicate (suchas Sr₂SiO₄, Ba₂SiO₄, Mn₂SiO₄), molybdate (SrMoO₄, BaMoO₄) and tungstate(BaWO₄, MgWO₄), which all have a low microwave dielectric constant andefficacious properties; however, the material of molybdate and tungstateare expensive. This silicate is most widely applied in this field due toits low dielectric constant and low material cost. Mg₂SiO₄ has a lowdielectric constant and high quality factor of 240000 GHz; however, thetemperature capacitance coefficient is relatively high up to −70 (ppm/°C.).

The prior art, CN 1315134, discloses a material system of Mg₂SiO₄ andMgTiO₃ that can reduce the temperature capacitance coefficienteffectively; however, its sintering temperature is higher than 1300° C.,making it impossible to be employed in the low-temperature co-firedprocess. Furthermore, literature in the prior art including CN101429015A has reported that Ca₂SiO₄ has a high quality factor and lowdielectric constant (8.6), but it belongs to a high-temperaturesintering material (>1200° C.). The prior art also discloses a Mg₂SiO₄having a low dielectric constant of 6 to 8, dielectric loss value lessthan 10⁻⁵ and the Qf value up to 160000 GHz. Such materials can beapplied in electronic circuit substrate, filter, microwave substratehigh frequency communication, but it has a high sintering temperature of1300-1500° C. Consequently, this sintering temperature is still too highfor it to be co-fired with Cu and Ag electrode.

The prior art also discloses a Li contained compound oxide ceramicLi₂Ba₃TiO₆ having a dielectric constant of 28-28.7, a quality factor of54000-79000 GHz, a temperature coefficient of about −7 ppm/° C. Thiscompound has a sintering temperature ranging from 1000 to 1040° C.,which is though lower than 300° C. sintering temperature of Mg₂SiO₄. Thesintering temperature is still too high to be co-fired with Cu, Ag etc.because of high sintering temperature restricting its industrialapplication.

The normal method for decreasing ceramic sintering temperature typicallycomprises: adding the oxide or glass material with low melting pointsuch as B₂O₃ or V₂O₅ etc. to produce a molten liquid phase at lowtemperature. The oxide or glass with low melting point benefit tosintering reaction of the ceramic material, leading to a decrease inoriginal sintering temperature. However, though using above manner candecrease original sintering temperature of ceramic material, theproperty of original material will be effected or the follow-upprocessing will meet difficulty due to different properties (such ashigh frequency dielectric property) between the adding material and theoriginal material.

In addition to decreasing the sintering temperature, the glass materialis processed into a slurry with the microwave dielectric material toderive a high frequency multilayer capacitor device, in which PVA or PVBis always utilized by the slurry system as a binder, and according tothe research report in prior art [J. Am. Ceram. Soc., 93 3049-3051(2010)] that there may be a cross-linking reaction between PVA or PVBand the flux B₂O₃ forming a three-dimensional (3-D) network gelstructure such that the viscosity of the slurry is significantlyincreased; therefore, it is harmful to the coating process and cannot beapplied to make a multilayer ceramic capacitor device. Unfortunately,however, the need persists for a material design employing a lowtemperature sintering process while also maintaining efficaciousprocessing and electrical properties of ceramic material.

SUMMARY OF THE INVENTION

To solve above technical disadvantages of conventional materials, thepresent invention is directed to providing a low-temperature co-firedmicrowave dielectric ceramic material and the preparation methodthereof, i.e. sintering into dense structure at a temperature of900-970° C. and co-firing with Ag in ambient environment and with Cu ininert atmosphere; a microwave dielectric ceramic material havingadvantageous properties including low dielectric constant (8-15), highquality factor (Q factor), low capacitance-temperature coefficient forapplications to such microwave dielectric devices as capacitor, ceramicfilter, ceramic antenna etc.

To further address technical problems of conventional materials, a yetfurther purpose of the present invention is to provide co-firing at lowtemperature by adding an eutectic composition and developing a new glassmaterial formulation. For ceramic powder comprising 30 wt %-80 wt %Mg₂SiO₄ and 20 wt %-70 wt % Ca₂SiO₄, there could be an eutecticcomposition. Thus, instead of sintering at 1300° C. into densityoriginally, the ceramic material with eutectic composition is sinteredinto dense structure only at 1150° C. Both Mg₂SiO₄ and Ca₂SiO₄ aremicrowave dielectric ceramics having a low dielectric constant, theireutectic phase material has the property of low dielectric constant andhigh quality factor. To further adjust the dielectric property of thismaterial formulation, additives CaTiO₃ and CaZrO₃ are mixed into theformulation. Next, the above ceramic material is combined into a glassslurry to compose a ceramic composite at a low sintering temperature(≤1000° C.) by liquid phase sintering of glass material.

To solve a yet further technical problem of conventional materials,another purpose of the present invention is to further provide a ceramiccomposite with the low temperature sintering by the property of liquidphase sintering of glass material, wherein a glass material comprisingLi₂O, BaO, SrO, CaO, B₂O₃, and SiO₂ has the property of high chemicalstability obtained by mixing the powder of Li₂O, BaO, SrO, CaO, B₂O₃ andSiO₂ to melt at 1000-1300° C.; the composed glass material also has highstructural stability in addition to provide the effect of sintering intoa dense structure at low temperature for the ceramic powder, and may notreact with water, methanol, ethanol, PVA and PVB, avoiding gel effect;and having efficacious plating resistance for conveniently applying tothe process for multilayer capacitor device.

The present invention provides a low-temperature co-fired microwavedielectric ceramic material, which comprises: (a) 85 wt % to 99 wt %ceramic material, which mainly comprises Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, andCaZrO₃, wherein a weight ratio of Mg₂SiO₄ relative to Ca₂SiO₄ is of(1-x):x, a weight ratio of CaTiO₃ relative to CaZrO₃ is of y:z, and aweight ratio of entities of Mg₂SiO₄ and Ca₂SiO₄ relative to CaTiO₃ is of(1-y-z):y, 0.2≤x≤0.7, 0.05≤y≤0.2, 0.05≤z≤0.4; and (b) 1 wt % to 15 wt %glass material mainly composed of Li₂O, BaO, SrO, CaO, B₂O₃, and SiO₂.

Preferably, Li₂O accounts for a wt % (0 wt %≤a wt %≤10 wt %) by weightof the glass material; BaO accounts for b wt % (1 wt %≤b wt %≤15 wt %)by weight of the glass material; SrO accounts for c wt % (1 wt %≤c wt%≤11 wt %) by weight of the glass material; CaO accounts for d wt % (5wt %≤d wt %≤23 wt %) by weight of the glass material; B₂O₃ accounts fore wt % (5 wt %≤e wt %≤30 wt %) by weight of the glass material; SiO₂accounts for f wt % (20 wt %≤f wt %≤50 wt %) by weight of the glassmaterial; and a wt %+b wt %+c wt %+d wt %+e wt %+f wt %=100 wt %.

Preferably, the dielectric constant of the low-temperature co-firedmicrowave dielectric ceramic material ranges from 8 to 15, the sinteringdensity distribution is of 3.17-3.52 (g/cm³), the quality factordistribution is of 2900-6500, and the insulation resistance property isof ≥3.5×10¹²Ω.

The present invention provides a preparation method for thelow-temperature co-fired microwave dielectric ceramic material, whichcomprises: (a) mixing ceramic precursor material of the ceramic materialwith glass precursor material of the glass material at room temperature,wherein the ceramic precursor material is composed of an eutectic phasecomposite of a Mg₂SiO₄ powder and a Ca₂SiO₄ powder with then addition ofadditives of a Mg₂SiO₄ powder and Ca₂SiO₄ powder; (b) sintering themixed material at a low temperature of 900-970° C. for 0.5-4 hours.

Preferably, the Mg₂SiO₄ powder is obtained by calcining MgO and SiO₂ at900-1300° C. for 4-10 hours and then grinding for refinement.

Preferably, the Ca₂SiO₄ powder is obtained by calcining CaO and SiO₂ at900-1200° C. for 4-10 hours and then grinding for refinement.

Preferably, the CaTiO₃ powder is obtained by calcining CaO and TiO₂ at900-1200° C. for 4-10 hours and then grinding for refinement.

Preferably, the CaZrO₃ powder is obtained by calcining CaO and ZrO₂ at900-1200° C. for 4-10 hours and then grinding for refinement.

Preferably, the glass precursor material is composed of 0-10 wt % Li₂Opowder, 1-15 wt % BaO powder, 1-11 wt % SrO powder, 5-23 wt % CaOpowder, 5-30 wt % B₂O₃ powder and 20-50 wt % SiO₂ powder, forming theglass material after the glass precursor material being melted at1000-1300° C. for 2-10 hours and then being ground for refinement.

The present invention provides another preparation method forlow-temperature co-fired microwave dielectric ceramic material, whichcomprises: (a) mixing ceramic precursor material of the ceramic materialwith glass precursor material of the glass material at room temperature,wherein the ceramic precursor material is composed of an eutectic phasecomposite composed by a Mg₂SiO₄ powder and Ca₂SiO₄ powder with additionof additives of a CaZrO₃ powder and CaTiO₃ powder; and (b) sintering themixed material with Ag or Cu electrode at a low temperature of 900-970°C. for 0.5-4 hours.

Preferably, the Mg₂SiO₄ powder is obtained by calcining MgO and SiO₂ at900-1300° C. for 4-10 hours and then grinding for refinement.

Preferably, the Ca₂SiO₄ powder is obtained by calcining CaO and SiO₂ at900-1200° C. for 4-10 hours and then grinding for refinement.

Preferably, the CaTiO₃ powder is obtained by calcining CaO and TiO₂ at900-1200° C. for 4-10 hours and then grinding for refinement.

Preferably, the CaZrO₃ powder is obtained by calcining CaO and ZrO₂ at900-1200° C. for 4-10 hours and then grinding for refinement.

Preferably, the glass precursor material is composed of 0-10 wt % Li₂Opowder, 1-15 wt % BaO powder, 1-11 wt % SrO powder, 5-23 wt % CaOpowder, 5-30 wt % B₂O₃ powder and 20-50 wt % SiO₂ powder, forming theglass material after the glass precursor material being melted at1000-1300° C. for 2-10 hours and then being ground for refinement.

The present invention provides a high frequency ceramic capacitor, whichcomprises: (a) a dielectric layer, which is mainly composed of thelow-temperature co-fired microwave dielectric ceramic material; (b) aninternal electrode, which is mounted on a surface of the dielectriclayer; and (c) two terminal electrodes, which are respectively mountedat two sides of the dielectric layer.

Preferably, the internal electrode is made of silver, palladium, nickel,or copper.

Preferably, the terminal electrode is made of silver, nickel, copper, ortin.

Preferably, each terminal electrode comprises: (c1) a substrate layer,which is mounted at one side of the dielectric layer; (c2) a barrierlayer, which is mounted on the substrate layer; and (c3) a solderinglayer, which is mounted on the barrier layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of low-temperature co-fired microwave dielectricceramic material and preparation method thereof of the presentinvention;

FIG. 2 is another flow chart of low-temperature co-fired microwavedielectric ceramic material and preparation method thereof of thepresent invention;

FIG. 3 is a schematic figure showing a high frequency ceramic capacitorof the present invention; and

FIG. 4 is the surface morphology of the low-temperature co-firedmicrowave dielectric ceramic material adding with glass material afterelectroplating.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The specific embodiments will be described as follows to illustrate theimplementing aspects of the present invention, but not limit the scopeintended to be protected by the present invention.

The first embodiment of the present invention provides a low-temperatureco-fired microwave dielectric ceramic material comprising: 85 wt % to 99wt % ceramic material and 1 wt % to 15 wt % glass material. Thedielectric constant of the above microwave dielectric ceramic materialis of a low dielectric constant ranging from 8 to 15, and while having amicrowave dielectric material with high quality factor and temperaturefrequency coeffecient close to zero, the sintering density distributionthereof being 3.17-3.52 (g/cm³), the quality factor distribution beingof 2900-6500, and the insulation resistance property being of≥3.5×10¹²Ω.

The ceramic material mainly comprises Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, andCaZrO₃. Through prior researching, for ceramic powder comprising Mg₂SiO₄and Ca₂SiO₄, if a weight ratio of Mg₂SiO₄ relative to Ca₂SiO₄ is of(1-x):x, 0.2≥x≥0.7, there could be an eutectic composition. Thetemperature for sintering the ceramic into dense structure may bedecreased from original 1300° C. to 1150° C. At the same time, thiseutectic phase material also has a property of low dielectric constantand high quality factor. Appropriate CaTiO₃ and CaZrO₃ are added forfurther adjustment of overall dielectric properties of the materialafter sintering, the ceramic material in the first embodiment of thepresent invention is then obtained, wherein a weight ratio of Mg₂SiO₄relative to Ca₂SiO₄ is of (1-x):x, a weight ratio of CaTiO₃ relative toCaZrO₃ is of y:z, and a weight ratio of entities of Mg₂SiO₄ and Ca₂SiO₄relative to CaTiO₃ is of (1-y-z):y, 0.2≤x≤0.7, 0.05≤y≤0.02, 0.05≤z≤0.4.

In the glass material, Li₂O accounts for a wt % (0 wt %≤a wt %≤10 wt %)by weight of the glass material; BaO accounts for b wt % (1 wt %≤b wt%≤15 wt %) by weight of the glass material; SrO accounts for c wt % (1wt %≤c wt %≤11 wt %) by weight of the glass material; CaO accounts for dwt % (5 wt %≤d wt %≤23 wt %) by weight of the glass material; B₂O₃accounts for e wt % (5 wt %≤e wt %≤30 wt %) by weight of the glassmaterial; SiO₂ accounts for f wt % (20 wt %≤f wt %≤50 wt %) by weight ofthe glass material, and a wt %+b wt %+c wt %+d wt %+e wt %+f wt % =100wt %.

With reference to FIG. 1, the second embodiment of the present inventionprovides a preparation method for low-temperature co-fired microwavedielectric ceramic material comprising:

(S01): wet-mixing ceramic precursor material of the ceramic materialwith glass precursor material of the glass material at room temperature,wherein the ceramic precursor material is composed of an eutectic phasecomposite and an additive, in which the eutectic phase composite iscomposed of a Mg₂SiO₄ powder and a Ca₂SiO₄ powder, the additive iscomposed of a CaZrO₃ powder and a CaTiO₃ powder; and

(S02): sintering the mixed material at a temperature of 900-970° C. for0.5-4 hours.

The ceramic precursor material is composed of Mg₂SiO₄ powder, Ca₂SiO₄powder, CaZrO₃ powder and CaTiO₃ powder. The Mg₂SiO₄ powder is preparedby weighing MgO and SiO₂ according to stoichiometric ratio thereof andcalcining them at 900-1300° C. for 4-10 hours and then grinding theobtained product for refinement. The Ca₂SiO₄ powder is prepared byweighing CaO and SiO₂ according to stoichiometric ratio thereof andcalcining them at 900-1200° C. for 4-10 hours and then grinding theobtained product for refinement. The CaTiO₃ powder is prepared byweighing CaO and TiO₂ according to stoichiometric ratio thereof andcalcining them at 900-1200° C. for 4-10 hours and then grinding theobtained product for refinement. The CaZrO₃ powder is prepared byweighing CaO and ZrO₂ according to stoichiometric ratio thereof andcalcining them at 900-1200° C. for 4-10 hours and then grinding theobtained product for refinement.

The glass precursor material is composed of 0-10 wt % Li₂O powder, 1-10wt % BaO powder, 1-10 wt % SrO powder, 5-20 wt % CaO powder, 5-30 wt %B₂O₃ powder and 10-50 wt % SiO₂ powder, forming the glass material ofLi₂O—BaO—SrO—CaO—B₂O₃—SiO₂ after the glass precursor material beingmelted at 1000-1300° C. for 2-10 hours and then being ground forrefinement. For the property of the glass material, in addition toprovide an advantageous liquid sintering property when glass precursormaterial being co-fired with ceramic precursor material, it also has ahigh chemical stability: not easily hydrolyzed in water or alcohol etc.and resistant to corrosion in electroplating baths (copper, nickel ortin).

After adding water, alcohol, dispersant etc. for wet-mixing the ceramicprecursor material with the glass precursor material for 2 hours, thenfiltering to dry. Sintering the mixed material at a low temperature of900-970° C., and may co-fire them with Ag or Cu for 0.5-4 hours, thenthe dielectric constant of the above microwave dielectric ceramicmaterial becomes a low dielectric constant ranging from 8 to 15, andwhile becoming a microwave dielectric material with high quality factorand temperature frequency coefficient close to zero, the sinteringdensity distribution thereof is of 3.17-3.52 (g/cm³), the quality factordistribution is of 2900-6500, and the insulation resistance property isof ≥3.5×10¹²Ω.

With reference to FIG. 2, the third embodiment of the present inventionprovides another preparation method for low-temperature co-firedmicrowave dielectric ceramic material comprising:

(S11): wet-mixing ceramic precursor material of the ceramic materialwith glass precursor material of the glass material of at roomtemperature, wherein the ceramic precursor material is composed of aneutectic phase composite and an additive, in which the eutectic phasecomposite is composed of a Mg₂SiO₄ powder and a Ca₂SiO₄ powder, theadditive is composed of a CaZrO₃ powder and a CaTiO₃ powder; and

(S12): sintering the mixed material with an Ag or Cu electrode at atemperature of 900-970° C. for 0.5-4 hours.

The preparation manner for ceramic material and glass material in thethird embodiment of the present invention is similar to that in thesecond embodiment, and will not be described in detail in the presentembodiment.

With reference to FIG. 3, the fourth embodiment of the present inventionprovides a high frequency ceramic capacitor comprising a dielectriclayer (1), an internal electrode (2), and two terminal electrodes (3).The high frequency ceramic capacitor has low tight tolerance oncapacitance value and low equivalent series resistance.

The dielectric layer (1) comprises the low-temperature co-firedmicrowave dielectric ceramic material as the embodiment above. Theinternal electrode (2) is positioned on a surface of the dielectriclayer (1), and is made of silver, palladium, nickel, or copper. Theterminal electrodes (3) are respectively mounted at two sides of thedielectric layer, and each is made of silver, nickel, copper, or tin. Inaddition, each terminal electrode (3) comprises a substrate layer (31),a barrier layer (32), and a soldering layer (33). The substrate layer(31) is mounted at one side of the dielectric layer (1), the barrierlayer (32) is mounted on the substrate layer (31), and the solderinglayer (33) is mounted on the barrier layer (32).

According to the formulation in the present invention: 85 wt % to 99 wt% ceramic material is mixed with 1 wt % to 15 wt % glass material, andafter mixing ceramic material in the proportion of different x, y and zwith that in different glass/ceramic ingredient proportions, pressinginto disk and coating Ag or Cu electrode onto the disk for co-firing,and then the physical and dielectric properties of different ceramiccomposites after sintering are shown in Table 1. Wherein, the qualityfactor is obtained by inversing the dispassion factor of sintered bodythat is measured through a capacitance meter at 1 MHz communicationsignal by way of biasing 1 Vrms; and for temperature-capacitancecoefficient measurement, ΔC/C, ΔC/C is obtained by observing thecapacitance variants ΔC at −55° C.-125° C. based on the devicecapacitance measured at room temperature of 25° C.

Experiment 1-1: with x=0.2, y=0.05, and z=0.02, ceramic material ismixed with 1 wt % glass material for co-firing test with Cu electrode at970° C. to prepare a low-temperature co-fired microwave dielectricceramic material with density of 3.23 (g/cm³); quality factor (Q) pointof 6250; dielectric constant and capacitance-temperature coefficient of8.5 and −14 ppm/° C. respectively; insulation resistance of 5.2×10¹²Ω.

Experiment 1-2: when x=0.2, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Ag electrode at 915°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.17 (g/cm³); quality factor (Q) of 5882;dielectric constant and capacitance-temperature coefficient of 8.1 and−15 ppm/° C. respectively; insulation resistance of 4.2×10¹²Ω.

Experiment 1-3: when x=0.2, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.28 (g/cm³); quality factor (Q) of 6666;dielectric constant and capacitance-temperature coefficient of 9.6 and18 ppm/° C. respectively; insulation resistance of 5.4×10¹²Ω.

Experiment 1-4: when x=0.2, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Ag electrode at 910°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.22 (g/cm³); quality factor (Q) point of 6250;dielectric constant and capacitance-temperature coefficient of 9.5 and19 ppm/° C. respectively; insulation resistance of 4.4×10¹²Ω.

Experiment 1-5: when x=0.2, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Cu electrode at 970° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.35 (g/cm³); quality factor (Q) of 4762;dielectric constant and capacitance-temperature coefficient of 11.8 and46 ppm/° C., respectively; insulation resistance of 3.9×10¹²Ω.

Experiment 1-6: when x=0.2, y=0.2, z=0.1, ceramic material is mixed with10 wt % Li₂O—BaO—SrO—CaO—B₂O₃—SiO₂ glass material for co-firing testwith Ag electrode at 905° C. to prepare a low-temperature co-firedmicrowave dielectric ceramic material with density of 3.32 (g/cm³);quality factor (Q) of 4545; dielectric constant andcapacitance-temperature coefficient of 11.9 and 37 ppm/° C.,respectively; insulation resistance of 3.5×10¹²Ω.

Experiment 1-7: when x=0.2, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.34 (g/cm³); quality factor (Q) of 4347;dielectric constant and capacitance-temperature coefficient of 11.9 and47 ppm/° C. respectively; insulation resistance of 3.7×10¹²Ω.

Experiment 1-8: when x=0.2, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Ag electrode at 900°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.31 (g/cm³); quality factor (Q) point of 4167;dielectric constant and capacitance-temperature coefficient of 12 and 40ppm/° C. respectively; insulation resistance property of 3.8×10¹²Ω.

Experiment 2-1: when x=0.4, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.25 (g/cm³); quality factor (Q) of 5263;dielectric constant and capacitance-temperature coefficient of 8.4 and−17 ppm/° C. respectively; insulation resistance property of 4.9×10¹²Ω.

Experiment 2-2: when x=0.4, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Ag electrode at 915°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.21 (g/cm³); quality factor (Q) point of 5000;dielectric constant and capacitance-temperature coefficient of 8.1 and−15 ppm/° C. respectively; insulation resistance property of 4.3×10¹²Ω.

Experiment 2-3: when x=0.4, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.30 (g/cm³); quality factor (Q) of 5555;dielectric constant and capacitance-temperature coefficient of 11.7 and17 ppm/° C. respectively; insulation resistance property of 5.6×10¹²Ω.

Experiment 2-4: when x=0.4, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Ag electrode at 910°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.25 (g/cm³); quality factor (Q) point of 5263;dielectric constant and capacitance-temperature coefficient of 11.6 and18 ppm/° C. respectively; insulation resistance of 4.7×10¹²Ω.

Experiment 2-5: when x=0.4, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Cu electrode at 970° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with sintering density distribution of 3.38 (g/cm³); qualityfactor (Q) point of 4545; dielectric constant andcapacitance-temperature coefficient of 11.8 and 46 ppm/° C.respectively; insulation resistance property of 4.8×10¹²Ω.

Experiment 2-6: when x=0.4, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Ag electrode at 905° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.42 (g/cm³); quality factor (Q) of 4347;dielectric constant and capacitance-temperature coefficient of 11.6 and44 ppm/° C. respectively; insulation resistance property of 3.9×10¹²Ω.

Experiment 2-7: when x=0.4, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.37 (g/cm³); quality factor (Q) point of 3846;dielectric constant and capacitance-temperature coefficient of 14.2 and47 ppm/° C. respectively; insulation resistance property of 4.4×10¹²Ω.

Experiment 2-8: when x=0.4, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Ag electrode at 900°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.40 (g/cm³); quality factor (Q) of 3704;dielectric constant and capacitance-temperature coefficient of 14 and 46ppm/° C. respectively; insulation resistance of 3.9×10¹²Ω.

Experiment 3-1: when x=0.5, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.28 (g/cm³); quality factor (Q) point of 4545;dielectric constant and capacitance-temperature coefficient of 8.5 and−17 ppm/° C. respectively; insulation resistance of 5.3×10¹²Ω.

Experiment 3-2: when x=0.5, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Ag electrode at 915°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.25 (g/cm³); quality factor (Q) point of 4347;dielectric constant and capacitance-temperature coefficient of 8.2 and−19 ppm/° C. respectively; insulation resistance of 4.3×10¹²Ω.

Experiment 3-3: when x=0.5, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.36 (g/cm³); quality factor (Q) of 4762;dielectric constant and capacitance-temperature coefficient of 9.6 and15 ppm/° C. respectively; insulation resistance property of 5.7×10¹²Ω.

Experiment 3-4: when x=0.5, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Ag electrode at 910°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with sintering density distribution of 3.32 (g/cm³); qualityfactor (Q) point of 4545; dielectric constant andcapacitance-temperature coefficient of 9.5 and 14 ppm/° C. respectively;insulation resistance property of 5.2×10¹²Ω.

Experiment 3-5: when x=0.5, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Cu electrode at 970° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with sintering density distribution of 3.45 (g/cm³); qualityfactor (Q) of 3846; dielectric constant and capacitance-temperaturecoefficient of 11.8 and 45 ppm/° C. respectively; insulation resistanceof 4.9×10¹²Ω.

Experiment 3-6: when x=0.5, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Ag electrode at 905° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with sintering density distribution of 3.41 (g/cm³); qualityfactor (Q) of 3571; dielectric constant and capacitance-temperaturecoefficient of 11.7 and 45 ppm/° C. respectively; insulation resistanceof 3.9×10¹²Ω.

Experiment 3-7: when x=0.5, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.44 (g/cm³); quality factor (Q) point of 3704;dielectric constant and capacitance-temperature coefficient of 11.9 and46 ppm/° C. respectively; insulation resistance of 4.4×10¹²Ω.

Experiment 3-8: when x=0.5, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Ag electrode at 900°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.42 (g/cm³); quality factor (Q) point of 3448;dielectric constant and capacitance-temperature coefficient of 12 and 47ppm/° C. respectively; insulation resistance of 4.0×10¹²Ω.

Experiment 4-1: when x=0.7, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.31 (g/cm³); quality factor (Q) point of 4000;dielectric constant and capacitance-temperature coefficient of 8.5 and−19 ppm/° C. respectively; insulation resistance of 5.3×10¹²Ω.

Experiment 4-2: when x=0.7, y=0.05, z=0.02, ceramic material is mixedwith 1 wt % glass material for co-firing test with Ag electrode at 915°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.26 (g/cm³); quality factor (Q) of 3846;dielectric constant and capacitance-temperature coefficient of 7.9 and−15 ppm/° C. respectively; insulation resistance of 5.1×10¹²Ω.

Experiment 4-3: when x=0.7, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.41 (g/cm³); quality factor (Q) point of 4167;dielectric constant and capacitance-temperature coefficient of 9.6 and14 ppm/° C. respectively; insulation resistance of 6.7×10¹²Ω.

Experiment 4-4: when x=0.7, y=0.1, z=0.05, ceramic material is mixedwith 5 wt % Li₂O—BaO—SrO—CaO—B₂O₃—SiO₂ glass material for co-firing testwith Ag electrode at 910° C. to prepare a low-temperature co-firedmicrowave dielectric ceramic material with density of 3.31 (g/cm³);quality factor (Q) point of 4000; dielectric constant andcapacitance-temperature coefficient of 9.4 and 15 ppm/° C. respectively;insulation resistance of 6.2×10¹²Ω.

Experiment 4-5: when x=0.7, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Cu electrode at 970° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.50 (g/cm³); quality factor (Q) point of 3448;dielectric constant and capacitance-temperature coefficient of 11.8 and45 ppm/° C. respectively; insulation resistance of 4.8×10¹²Ω.

Experiment 4-6: when x=0.7, y=0.2, z=0.1, ceramic material is mixed with10 wt % glass material for co-firing test with Ag electrode at 905° C.to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.43 (g/cm³); quality factor (Q) point of 3226;dielectric constant and capacitance-temperature coefficient of 11.6 and39 ppm/° C. respectively; insulation resistance of 4.7×10¹²Ω.

Experiment 4-7: when x=0.7, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Cu electrode at 970°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.52 (g/cm³); quality factor (Q) point of 3125;dielectric constant and capacitance-temperature coefficient of 11.9 and46 ppm/° C. respectively; insulation resistance of 4.6×10¹²Ω.

Experiment 4-8: when x=0.7, y=0.3, z=0.15, ceramic material is mixedwith 15 wt % glass material for co-firing test with Ag electrode at 900°C. to prepare a low-temperature co-fired microwave dielectric ceramicmaterial with density of 3.46 (g/cm³); quality factor (Q) point of 2941;dielectric constant and capacitance-temperature coefficient of 11.8 and44 ppm/° C. respectively; insulation resistance of 4.3×10¹²Ω.

As shown in Table 1, the density of sintered body raises with the addingamount of glass increases and the sintering density distribution is3.17-3.52 (g/cm³); the quality factor property correlates with theadding proportion of main material with high microwave property and thedensity after sintering, and the quality factor distribution is2914-6250; the dielectric constant and capacitance-temperaturecoefficient falls on respectively: 8.1-14.2 and −19-46 ppm/° C. In all,after being sintered with Ag or Cu, the sintered material has lowdielectric constant property, and high quality factor, efficacioustemperature-capacitance coefficient and high insulation resistanceproperty (≥3.7×10¹²Ω).

With reference to Table 2, results of sintering property are shown when90 wt % ceramic material (x=0.5, y=0.2, z=0.1) is mixed with 10 wt %glass material with different formulation at 900° C. The componentsadding into the glass material are: Li₂O accounting for a wt % by weightof the glass material, 0 wt %≤a wt %≤10 wt %; BaO accounting for b wt %by weight of the glass material, 1 wt %≤b wt %≤15 wt %; SrO accountingfor c wt % by weight of the glass material, 1 wt %≤c wt %≤11 wt %; CaOaccounting for d wt % by weight of the glass material, 5 wt %≤d wt %≤23wt %; B₂O₃ accounting for e wt % by weight of the glass material, 5 wt%≤e wt %≤30 wt %; SiO₂ accounting for f wt % by weight of the glassmaterial, 20 wt %≤f wt %≤50 wt %, wherein a wt %+b wt %+c wt %+d wt %+ewt %+f wt % =100 wt %.

Experiment 5-1: when 90 wt % ceramic material (x indicates a ratio valueof a weight of Ca₂SiO₄ relative to a sum weight of Ca₂SiO₄ and Mg₂SiO₄,x=0.5; y indicates a ratio value of a weight of CaTiO₃ relative to a sumweight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, y=0.2; z indicates aratio value of a weight of CaZrO₃ relative to a sum weight of Mg₂SiO₄,Ca₂SiO₄, CaTiO₃, and CaZrO₃, z=0.1) being mixed with 10 wt % glassmaterial with different formulation is co-fired with Cu electrode at970° C. Wherein, the components adding into the glass material are: Li₂Oaccounting for 10 wt % by weight of the glass material; BaO accountingfor 10 wt % by weight of the glass material; SrO accounting for 11 wt %by weight of the glass material; CaO accounting for 14 wt % by weight ofthe glass material; B₂O₃ accounting for 5 wt % by weight of the glassmaterial; SiO₂ accounting for 50 wt % by weight of the glass material.The prepared low-temperature co-fired microwave dielectric ceramicmaterial has a density of 3.45 (g/cm³); quality factor (Q) point of3846; dielectric constant and capacitance-temperature coefficient of11.8 and 45 ppm/° C. respectively; insulation resistance of 4.9×10¹²Ω.

Experiment 5-2: when 90 wt % ceramic material (x indicates a ratio valueof a weight of Ca₂SiO₄ relative to a sum weight of Ca₂SiO₄ and Mg₂SiO₄,x=0.5; y indicates a ratio value of a weight of CaTiO₃ relative to a sumweight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, y=0.2; z indicates aratio value of a weight of CaZrO₃ relative to a sum weight of Mg₂SiO₄,Ca₂SiO₄, CaTiO₃, and CaZrO₃, z=0.1) being mixed with 10 wt % glassmaterial with different formulation is co-fired with Cu electrode at935° C. Wherein, the components adding into the glass material are: Li₂Oaccounting for 9 wt % in the glass material by weight of the glassmaterial; BaO accounting for 1 wt % by weight of the glass material; SrOaccounting for 10 wt % by weight of the glass material; CaO accountingfor 5 wt % by weight of the glass material; B₂O₃ accounting for 29 wt %by weight of the glass material; SiO₂ accounting for 46 wt % by weightof the glass material. The prepared low-temperature co-fired microwavedielectric ceramic material has a density of 3.4 (g/cm³); quality factor(Q) point of 3923; dielectric constant and capacitance-temperaturecoefficient of 12.3 and 40 ppm/° C. respectively; insulation resistanceof 5.9×10¹²Ω.

Experiment 5-3: when 90 wt % ceramic material (x indicates a ratio valueof a weight of Ca₂SiO₄ relative to a sum weight of Ca₂SiO₄ and Mg₂SiO₄,x=0.5; y indicates a ratio value of a weight of CaTiO₃ relative to a sumweight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, y=0.2; z indicates aratio value of a weight of CaZrO₃ relative to a sum weight of Mg₂SiO₄,Ca₂SiO₄, CaTiO₃, and CaZrO₃, z=0.1) being mixed with 10 wt % glassmaterial with different formulation is co-fired with Cu electrode at960° C. Wherein, the components adding into the glass material are: Li₂Oaccounting for 8 wt % by weight of the glass material; BaO accountingfor 10 wt % by weight of the glass material; SrO accounting for 8 wt %by weight of the glass material; CaO accounting for 19 wt % by weight ofthe glass material; B₂O₃ accounting for 20 wt % by weight of the glassmaterial; SiO₂ accounting for 35 wt % by weight of the glass material.The prepared low-temperature co-fired microwave dielectric ceramicmaterial has a density of 3.35 (g/cm³); quality factor (Q) point of4005; dielectric constant and capacitance-temperature coefficient of12.6 and 35 ppm/° C. respectively; insulation resistance of 6.2×10¹²Ω.

Experiment 5-4: when 90 wt % ceramic material (x indicates a ratio valueof a weight of Ca₂SiO₄ relative to a sum weight of Ca₂SiO₄ and Mg₂SiO₄,x=0.5; y indicates a ratio value of a weight of CaTiO₃ relative to a sumweight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, y=0.2; z indicates aratio value of a weight of CaZrO₃ relative to a sum weight of Mg₂SiO₄,Ca₂SiO₄, CaTiO₃, and CaZrO₃, z=0.1) being mixed with 10 wt % glassmaterial with different formulation is co-fired with Cu electrode at930° C. Wherein, the components adding into the glass material are: Li₂Oaccounting for 5 wt % by weight of the glass material; BaO accountingfor 14 wt % by weight of the glass material; SrO accounting for 10 wt %by weight of the glass material; CaO accounting for 23 wt % by weight ofthe glass material; B₂O₃ accounting for 28 wt % by weight of the glassmaterial; SiO₂ accounting for 20 wt % by weight of the glass material.The prepared low-temperature co-fired microwave dielectric ceramicmaterial has a density of 3.38 (g/cm³); quality factor (Q) of 4265;dielectric constant and capacitance-temperature coefficient of 11.8 and37 ppm/° C. respectively; insulation resistance of 7.9×10¹²Ω.

Experiment 5-5: when 90 wt % ceramic material (x indicates a ratio valueof a weight of Ca₂SiO₄ relative to a sum weight of Ca₂SiO₄ and Mg₂SiO₄,x=0.5; y indicates a ratio value of a weight of CaTiO₃ relative to a sumweight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, y=0.2; z indicates aratio value of a weight of CaZrO₃ relative to a sum weight of Mg₂SiO₄,Ca₂SiO₄, CaTiO₃, and CaZrO₃, z=0.1) being mixed with 10 wt % glassmaterial with different formulation is co-fired with Cu electrode at920° C. Wherein, the components adding into the glass material are: Li₂Oaccounting for 0 wt % by weight of the glass material; BaO accountingfor 15 wt % by weight of the glass material; SrO accounting for 1 wt %by weight of the glass material; CaO accounting for 17 wt % by weight ofthe glass material; B₂O₃ accounting for 30 wt % by weight of the glassmaterial; SiO₂ accounting for 37 wt % by weight of the glass material.The prepared low-temperature co-fired microwave dielectric ceramicmaterial has a density of 3.33 (g/cm³); quality factor (Q) point of4201; dielectric constant and capacitance-temperature coefficient of12.5 and 40 ppm/° C. respectively; insulation resistance of 3.9×10¹²Ω.

As shown in Table 2, the quality factor is in the range from 3846 to4065; the dielectric constant and capacitance-temperature coefficientranges from 11.8 to12.5 and from 35 to 45 ppm/° C., respectively. Inall, after being sintered with Cu, the sintered material has lowdielectric constant and efficacious temperature-capacitance coefficientand insulation resistance property (≥3.7×10¹²Ω). The ceramic slipprepared by alcohol with toluene and polyvinyl butyral (PVB) was astable slip did not react with PVB and thus the gel effect did notoccur, the slip viscosity being 350-450 cps; and the ceramic body madethrough sintering has a good anti-corrosion properties in platingsolution, which has pH value less than 3. FIG. 4 shows a surfacemorphology of the microwave dielectric material after electroplating,which has no pinhole on the surface.

Experiment 6: a low-temperature co-fired microwave dielectric ceramicmaterial is provided, which has dielectric constant coefficient of 9.6and quality factor (Q) point of 6666 and comprises 95 wt % ceramicmaterial (x indicates a ratio value of a weight of Ca₂SiO₄ relative to asum weight of Ca₂SiO₄ and Mg₂SiO₄, x=0.2; y indicates a ratio value of aweight of CaTiO₃ relative to a sum weight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃,and CaZrO₃, y=0.1; z indicates a ratio value of a weight of CaZrO₃relative to a sum weight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃,z=0.05) and 5 wt % glass material. Then, the dielectric ceramic materialis mixed with ethanol, toluene, a dispersant, and a binder by ballmilling technique to form a ceramic slip. After the slip is casted intofoils, internal Cu electrode paste is printed on each foil in athickness of 2.0-3.5 μm. After which, the foils are stacked, laminated,and cut to form a lamination. The binder is burnt out from thelamination at 150-450° C., and then the lamination is sintered at 970°C. under a N₂ atmosphere. After the tumbling process, terminalelectrodes are pasted on the sintered lamination by termination dippingtechnique, and cured under a N₂ atmosphere. A Ni layer (thickness of 2μm) and a Sn layer (thickness of 4-6 μm) are sequentially plated on eachterminal electrode so that 0201 capacitors with various capacitances of0.1±0.02-1.0±0.02 pF are produced. As shown in Table 3, as compared withthe commercial product AVX Accu-P® 0201 Thin-Film RF/MicrowaveCapacitor, the 0201 capacitors obtained in the experiment have lowerequivalent series resistance, and exhibit low energy consumption,especially at high frequency (2 GHz).

Many changes and modifications in the above described embodiment of theinvention can, of course, be carried out without departing from thescope thereof. Accordingly, to promote the progress in science and theuseful arts, the invention is disclosed and is intended to be limitedonly by the scope of the appended claims.

TABLE 1 Results of sintering property are shown when (100-m)wt % ceramicmaterial is mixed with (m)wt % glass material with different formulationat 900° C. (CS: Ca₂SiO₄; MS: Mg₂SiO₄, CT: CaTiO₃, CZ: CaZrO₃; x: a ratiovalue of a weight of Ca₂SiO₄ relative to a sum weight of Ca₂SiO₄ andMg₂SiO₄; y: a ratio value of a weight of CaTiO₃ relative to a sum weightof Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃; z: a ratio value of a weight ofCaZrO₃ relative to a sum weight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃)Sintering Temperature- Ceramic x 1-x y z Glass temper- co- Dielec-Qality capacitance Insulation material value value value value materialature firing density tric factor coefficient resistance Item (1-m wt %)(CS) (MS) (CT) (CZ) (m wt %) (° C.) metal (g/cm³) constant (Q) (ppm/°C.) (Ω) Test 1-1 99 0.2 0.8 0.05 0.02 1 970 Cu 3.23 8.5 6,250 −145.2*10¹² Test 1-2 915 Ag 3.17 8.1 5,882 −15 4.2*10¹² Test 1-3 95 0.10.05 5 970 Cu 3.28 9.6 6,666 18 5.4*10¹² Test 1-4 910 Ag 3.22 9.5 6,25019 4.4*10¹² Test 1-5 90 0.2 0.1 10 970 Cu 3.35 11.8 4,762 46 3.9*10¹²Test 1-6 905 Ag 3.32 11.9 4,545 37 3.5*10¹² Test 1-7 85 0.3 0.15 15 970Cu 3.34 11.9 4,347 47 3.7*10¹² Test 1-8 900 Ag 3.31 12 4,167 40 3.8*10¹²Test 2-1 99 0.4 0.6 0.05 0.02 1 970 Cu 3.25 8.4 5,263 −17 4.9*10¹² Test2-2 915 Ag 3.21 8.1 5,000 −15 4.3*10¹² Test 2-3 95 0.1 0.05 5 970 Cu3.30 11.7 5,555 17 5.6*10¹² Test 2-4 910 Ag 3.25 11.6 5,263 18 4.7*10¹²Test 2-5 90 0.2 0.1 10 970 Cu 3.38 11.8 4,545 46 4.8*10¹² Test 2-6 905Ag 3.42 11.6 4,347 44 3.9*10¹² Test 2-7 85 0.3 0.15 15 970 Cu 3.37 14.23,846 47 4.4*10¹² Test 2-8 900 Ag 3.40 14 3,704 46 3.9*10¹² Test 3-1 990.5 0.5 0.05 0.02 1 970 Cu 3.28 8.5 4,545 −17 5.3*10¹² Test 3-2 915 Ag3.25 8.2 4,347 −19 4.3*10¹² Test 3-3 95 0.1 0.05 5 970 Cu 3.36 9.6 4,76215 5.7*10¹² Test 3-4 910 Ag 3.32 9.5 4,545 14 5.2*10¹² Test 3-5 90 0.20.1 10 970 Cu 3.45 11.8 3,846 45 4.9*10¹² Test 3-6 905 Ag 3.41 11.73,571 45 3.9*10¹² Test 3-7 85 0.3 0.15 15 970 Cu 3.44 11.9 3,704 464.4*10¹² Test 3-8 900 Ag 3.42 12 3,448 47 4.0*10¹² Test 4-1 99 0.7 0.30.05 0.02 1 970 Cu 3.31 8.5 4,000 −19 5.3*10¹² Test 4-2 915 Ag 3.26 7.93,846 −15 5.1*10¹² Test 4-3 95 0.1 0.05 5 970 Cu 3.41 9.6 4,167 146.7*10¹² Test 4-4 910 Ag 3.31 9.4 4,000 15 6.2*10¹² Test 4-5 90 0.2 0.110 970 Cu 3.50 11.8 3,448 45 4.8*10¹² Test 4-6 905 Ag 3.43 11.6 3,226 394.7*10¹² Test 4-7 85 0.3 0.15 15 970 Cu 3.52 11.9 3,125 46 4.6*10¹² Test4-8 900 Ag 3.46 11.8 2,941 44 4.3*10¹²

TABLE 2 Results of sintering property are shown when 90 wt % ceramicmaterial (x indicates a ratio value of a weight of Ca₂SiO₄ relative to asum weight of Ca₂SiO₄ and Mg₂SiO₄, x = 0.5; y indicates a ratio value ofa weight of CaTiO₃ relative to a sum weight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃,and CaZrO₃, y = 0.2; z indicates a ratio value of a weight of CaZrO₃relative to a sum weight of Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, z =0.1) is mixed with 10 wt % glass material with different formulation at900° C. Sintering Temperature- Li₂O BaO SrO CaO B₂O₃ SiO₂ Slurry temper-Co- Den- Dielec- Quality capacitance Insulation (wt (wt (wt (wt (wt (wtviscos- ature firing sity tric Factor coefficient resistance %) %) %) %)%) %) ity (° C.) metal (g/cm³) constant (Q) (ppm/° C.) (Ω) Test 5-1 1010 11 14 5 50 350 970 Cu 3.45 11.8 3,846 45 4.9*10¹² Test 5-2 9 1 10 529 46 400 935 Cu 3.4 12.3 3,923 40 5.9*10¹² Test 5-3 8 10 8 19 20 35 430960 Cu 3.35 12.6 4,005 35 6.2*10¹² Test 5-4 5 14 10 23 28 20 450 930 Cu3.38 11.8 4,265 37 7.9*10¹² Test 5-5 0 15 1 17 30 37 400 920 Cu 3.3312.5 4,201 40 3.9*10¹²

TABLE 3 Results of equivalent series resistance values are shown whenthe 0201 capacitors of the present invention and the commercial 0201capacitors work under 2 GHz. Capacitances Commercial (pF) capacitor Test6 0.1 ± 0.02 2.28 2.02 0.3 ± 0.02 1.55 0.9 0.5 ± 0.02 0.85 0.13 0.7 ±0.02 0.63 0.08 1.0 ± 0.02 0.33 0.06

What is claimed is:
 1. A low-temperature co-fired microwave dielectricceramic material comprising: (a) 85 wt % to 99 wt % ceramic materialcomprising Mg₂SiO₄, Ca₂SiO₄, CaTiO₃, and CaZrO₃, wherein a weight ratioof Mg₂SiO₄ relative to Ca₂SiO₄ is of (1-x):x, a weight ratio of CaTiO₃relative to CaZrO₃ is of y:z, and a weight ratio of entities of Mg₂SiO₄and Ca₂SiO₄ relative to CaTiO₃ is of (1-y-z):y, 0.2≤x≤0.7, 0.05≤y≤0.2,0.05≤z≤0.4; and (b) 1 wt % to 15 wt % glass material composed of Li₂O,BaO, SrO, CaO, B₂O₃, and SiO₂.
 2. The low-temperature co-fired microwavedielectric ceramic material according to claim 1, wherein Li₂O accountsfor a wt % (5 wt %≤a wt %≤10 wt %) by weight of the glass material; BaOaccounts for b wt % (1 wt %≤b wt %≤15 wt %) by weight of the glassmaterial; SrO accounts for c wt % (1 wt %≤c wt %≤11 wt %) by weight ofthe glass material; CaO accounts for d wt % (5 wt %≤d wt %≤23 wt %) byweight of the glass material; B₂O₃ accounts for e wt % (5 wt %≤e wt %≤30wt %) by weight of the glass material; SiO₂ accounts for f wt % (20 wt%≤f wt %≤50 wt %) by weight of the glass material; and a wt %+b wt %+cwt %+d wt %+e wt %+f wt % =100 wt %.
 3. The low-temperature co-firedmicrowave dielectric ceramic material according to claim 1, wherein adielectric constant of the low-temperature co-fired microwave dielectricceramic material ranges from 8 to 15, a density thereof is in the rangefrom 3.17 to 3.52 (g/cm³), a quality factor thereof ranges from 2900 to6500, and an insulation resistance thereof is of ≥3.7×10¹²Ω.
 4. A highfrequency ceramic capacitor comprising: (a) a dielectric layer composedof the low-temperature co-fired microwave dielectric ceramic materialaccording to claim 1; (b) an internal electrode mounted on a surface ofthe dielectric layer; and (c) two terminal electrodes respectivelymounted at two sides of the dielectric layer.
 5. The high frequencyceramic capacitor according to claim 4, wherein Li₂O accounts for a wt %(5 wt %≤a wt %≤10 wt %) by weight of the glass material; BaO accountsfor b wt % (1 wt %≤b wt %≤15 wt %) by weight of the glass material; SrOaccounts for c wt % (1 wt %≤c wt %≤11 wt %) by weight of the glassmaterial; CaO accounts for d wt % (5 wt %≤d wt %≤23 wt %) by weight ofthe glass material; B₂O₃ accounts for e wt % (5 wt %≤e wt %≤30 wt %) byweight of the glass material; SiO₂ accounts for f wt % (20 wt %≤f wt%≤50 wt %) by weight of the glass material; and a wt %+b wt %+c wt %+dwt %+e wt %+f wt % =100 wt %.
 6. The high frequency ceramic capacitoraccording to claim 4, wherein a dielectric constant of thelow-temperature co-fired microwave dielectric ceramic material rangesfrom 8 to 15, a density thereof is in the range from 3.17 to 3.52(g/cm³), a quality factor thereof ranges from 2900 to 6500, and aninsulation resistance thereof is of ≥3.7×10²Ω.